Xwalter l louis krahl



May 10, 1932. w` 1 KRAHL 1,857,647

UNITARY ELEMENT STRUCTURE FOR VACUUM TUBES Filed oct. 2, 1929 IHHHHHHHHHHHHHHHHHHHH'HW IIIIHIHIHJHIIIII ATTORNEY Patented May 10, 1932 l UNITE, sA'rEs PATENT WALTER LOUrs KRAHL, or MONTCLAIR, NEwJERsEY, AssIGNOR To ARcTURUs RADIO A TUBE COMPANY, OE NEWARK, NEWVJERSEY, A CORPORATION or DELAWARE UNITARY ELEMENT STRUCTURE FOR VACUUM TUBES y Application filed October 2, 1929. Serial No. 396,668.

This invention relates to vacuum tubes and has for its principal obj ect to provide a means to mount the elements in. a vacuum tube whereby they form' a single unit which 1s 5 easily supported upon the` press.

AnotherV objectl of theinvention is to provide a unitary structurefor vacuum tube elements in which the elements maybe spaced in very close proximity with each other without any dangerof touching.

Another object of the invention is to provide a means to support a filament in a vacuum tube in such a mannerthat it cannot touch the adjacent element. l

Another object ofthe invention is to provide a unitary structure for vacuum tubes,

Ywhereby the elements mayeXp and or contractlongitudinally with temperature changes without changing the space relation with respect to the other elements.

Another object ofthe invention is to provide an anode structure in which the effective anode surface will not be moved with respect to the grid and cathode by slight movement ofthe anode supporting means.

Other objects of the inventionv and objects relating vparticularly to `methods of manufacturingy and assembling the various parts will be apparentv as the description of the invention proceeds. 1

One embodiment of this invention has been illustrated in the accompanying drawings, inwhich Fig. 1 is a front elevational view of a vacuum tube with portions of the envelope broken away to show 'the unitary element.

structure.

Fig. 2 is a sectional planview taken on the lines 2-2 of Fig. land showing the element structure;

Fig. 3 isa sectional side view of the element structure shown in Fig. 1 and taken on the line 3,-3 of Fig. l1; V l

l is,l a sectional front elevation .of the element 'structure' and takenl throughthe A center thereof; and..

Fig. 5 is a sectional detail view showing the spring for supportingone of the filaments.

Vwhich are attached the filament contact" 12, la grid contact 13, and a plate or anode contact 111. The envelope 10 has an integrally formed press 15 extending upwardly within the envelope in the usual manner and adapted to support the elements of the tube. y

A pair of insulating plates v16 and 17 are spaced apart and adapted to secure in rigid position between them the anode 18," the grid 19, and the filaments 20 and 21`. To accom-` plish this the anode 18 is mounted upon a pair of parallel upright metallic posts 22 which pass through holes 23 in the plate 16 and holes 24 in the plate 17 Vextending prefer-v ably farther below the plate 17 than above the plate 16. Y 7

Vliere each of the posts `22 pass through one of the insulating plates 16 and 17 a clip 25 is provided to hold it rigid with respect to theplate.-l These clips have a- U-shaped member 26 which lis adapted to eXtendfover the edge ofthe insulating plateto va point adjacent the post opening where the flanges 27 extend at right angles and are provided with grooves to lit the contour` ofthe supporting vpost 22 wheninserted through the opening in the plate. This clip is similar to that shown and described yin myco-pending application entitled Unitary vacuum tube structure, Serial No. 378,163, filed July 13, 1929( When the flanges 27 both above and below the insulating .plates 16 land 17 are welded to the posts 22 a'rigid structure is obtained, the support rods being maintained at right angle. to the insulating plates and held securely without permitting any {movement with respect thereto.

Thegrid 19 comprises la flattenedhelix of wiref28, the turns ofwhich are secured to two parallel upright posts 29 which-inv turn pass through openings 30 in the plate 16, and

31 in the plate 17 `.extending beyond the two 25, but I have not shown any clips on the supporting posts 29 because I prefer to have the helix forming the grid extend from one plate to the other, thus positioning the grid with respect to the plate but at the same time permitting some slight movementl of the grid posts-to allow for expansion. and contraction upon temperature changes.

Yillustration of my rnovel means of supporting the fllament, EI- have shown' V-two V-shape'dfilaments20and 21 supported at their lower ends uponthree posts 32,33, and 34, which also pass'throu'gh' holes provided for that purpose in the plates-16 and.17,-eXtend ing above the plate 16 and below the plate 17. .Thesesupportingposts pass throughv holes 35, 3.6,- 37 respectively inthe-plates` 16 and through -holesf38," .39 and `40 respectively.' in fthe I plate 117.` The Vshaped filament'20is positioned xbetweenf vthe postl 32; and the #center post 33, and the filament 21 is positioned. between the centerfpost:33;1andtheother :post 34.k .The twolowerends of each'lilamentare welded togthe postsin theimannershown in Fig. V4 at a point .adjacent thelower insulatingzplate `17. Theinp'per oriloop -end of theililaments *2O and 21 Y `are, supported respectively .upon

rhooks '41 and `v42 which extends fthrough openings42 in the upper vinsulatinguplate 'lpand zare=urged Vupwardly by coil springs .-,43' -which maydoe vformed as lapart of the hook members 41 as'cle-arly.illustratedin theenlarged vview in Iig. 5. Thespring is Ipreferably spiral so thatthebase` rests upon the plate and is large enough toipreventiit freni passing':through the opening therein. :It will bel understood that the springs 43 place a tension on each :filament fto .maintain the `filament taut and free from contactwith any 4of `the votherfparts of the tube. The three posts 32,1313,-and34 may berigidly `secured to the upper insulating :plate 16 by vrmeans of the clips 25.already1described in connec- Vtion-withfthe posts 22 'for the anode. Also,

' if. desired,theseA clipsmay be appliedat the lower insulating plate 17, and I havelshown Ythem secured` tothe outerlilament support 32 .and 34, but aslong asthese.supportsare well -Secured to the upper insulating plate 16 it is not lnecessary to vprovide additional clips-.in the lowerend but it` may be preferable ito .omit them sothattheposts may expand-and contract 'freelywith lrespect tothe plate 17. A; plurality of support wires may be sealed in the-press 15to'pro`vide ameans :for supporting the element vunit upon vthe press. I have'shown apair-of such-wires 44'adapted toconnect VVwith the posts22, another pair 45 -to 'connect with :the grid posts 29, and, :in Aorder to connect with-the outer'fiilament posts 32and l34, I-have also shown support -wiresv46 andv 47 respectively, .sealed Iin the ,press 15pandformingthe electricalconnec- `,tion -for fthe filament. These support --wires 44, 4,5, 46and 47 mayfbe'bent 'at right angles additional support 48 spaced from the ele-1 ments and extending above and'below them. This support48 may `bewelded-at4 itsy lower end to an.-angular support"49,seale'd-in the press 15 at the center thereof and bent backwardly at an angle to meet the support 48.

/ To connectthersupport 48 to the element unit a yoke 50 may be welded at its central point .-tote support=48 and mayzbe bentf outwardly and :forwardly to .engages-thetupper ends-of -the anode `posts 22. :1A y.similarryokeg:511may ibey attachedfin 1a similarimannersto the posts 22 at the lower end-thereof; andY may: 'beweldfV ed ,to Vthe `support- 48: .ati-tszmidpoint. The quadrilatenal `thusformedv i by'f-fthe elements,

Vyokes. and support/48,. (.see'-Figfy having nweldedcornerjoints, provides a mounting for the unitary; element structuremhichpermits little or1 no movement iwith.yrespectr-.ztoathe press.

ffl-he methd :off constructing fthefanode 18 and attaching itstofthe posts, fforms: an gimport ant :feature: of z the invention. V-Asishown .in fFig., 2 f the anode comprises .two i members 52 .made exactlyy alike. andnadapte'd tobe' secured together ftofrformi the complete anode. Eachfofxthe `members `52") haslaazsnbstantially flat anode surtace'53,1.whichzisladapteditozbe positioned: at; a1predeterminedf distanceefrom i the kcathode and vgrid* of*` theftube,:end flanges l54 at right ang-les; to the anodesu-rface 53,-.and K additional right; angle` flanges1155-onthe-end iianges ..54nand parallgel. '.with -theifanodetsurai' f :face i 53 ,ftof attach the two members z together e and i to Cattach-'the VAwhole a unit-:to f the 4supp orting posts 22. fIn orders'tofprevent any 'distorntion of thcfanodelsurface53; 'Iiprovide flanges ployed as bythe embossed circle 57 andfother make the anode surface 53 substantiallyfrigid VLso thatit; doesnot-.warp`V or. bend.

Special @note .should .be taken fof .the -fa'ct that the flanges 54 are bent at right angles 3';

to anode surfaces 53 andtheattaching flanges 55 are bent at right angleszto. thei flanges-.5.4. I have rfound that very ,slight vchanges ==with Arespect to the spacing betweenwthe cathode andanode willv cause considerable changefin the characteristics ofthe tubewhenineoperationand this occurs in "the `usual tube-con- ;struction as any-movement of the anode supporting posts *tends to wwarp the'am'de surface causing portions of it to move with re- 56 at each end thereof,.theseiangesabeingfibent at anangleftofthe surtacegandiife'desired,

additional re-enforcing devices may :be 1emspect to the cathode and grid. In the present construction any change in the position of the anode supporting posts 22 is taken up by the bending ofthe flanges 54 where they connect with the anode surface and with the flanges 55, and the eEect on the spacing between the anode and vother elements is so slight as to cause very little difference in the characteristics of the tube.

The anode flanges 55 are provided, of course, withV means to secure them to the supporting posts as by the grooves 58 pressed in the ends thereof which fit around the supporting posts 22 as clearly indicated in Fig. 2. The two members 52 may be secured together by riveting or by inserting portions of one through openings in the other as indicated. In assembling the element structure the posts 32, 33 and 34 would be set in a jig spaced apart as indicated in Fig. 4, and the filaments welded at their lower ends to the posts as indicated. Then the insulating plate 16 is inserted over the ends of the posts 32, 33, and 34 and after the spring members 43 are positioned in place and properly hooked under the loop of each filament, the insulator 16 is raised slightly, placing the spring 43 under compression andthe filaments under tension and the clips are then securely attached to the posts by welding to hold them rigidly with respect to the insulator. The grid posts 29 with the grid helix already attached may then be inserted in the openings provided for that purpose in the insulator 16, and the anode posts 22 with the anode attached thereto may also be inserted inthe holes 23 provided in the plate 16. Clips 25 may be attached then to the anode posts securing them rigidly to the plate 16 and the bottom insulator 17 may then be positioned on the lower end of the various supports with the support passing through the holes provided for that purpose in the insulator 17. Clips 25 may then be welded to the lower ends of any r of the support posts where they pass through the insulator 17 although it is only necessary to use the clips on enough of the posts to maintain the two insulators rigidly spaced from each other. I prefer to put the clips on the two anode support posts 22 as indicated. The yolres and 51 may then be welded to the posts 22 at the top and bottom as indicated, and the upright 48 may be welded tothe center point of these two yoles, or the yokes and the support 48 may be left until the element is mounted inthe tube.

The supporting posts are cut ofi'l below the elements at such a length that they will conveniently cooperate with the short wire supports which are sealed in the press of the tube, and when it is desired to mount an element unit upon a `press it is only necessary to hold the element in alignment with the press and wires sealed therein and weld each post to its cooperating press support. The

vcentral angular support 29 isf theniwelded to the upright 48 and themounting of the tube on the press is complete. v

,As indicated in Fig. 1, the lila-ment ter-` minal. 12 is connected to the support rod wire 46V by means of a wire 60, while the support wire 47 is connected to the other filament terminal 12 `by means of thewire 61. In like manner the support wire 45 is connected to the Vgrid terminal 13 by means of the wire 575 62 while the support wire 44 is connected to the plate terminal 14 by means of the 'wire 63. Thus the anode is connected through one of the posts 22, one of the support wires ,y

44, and the wire 63 to the plate terminal 14 at the vbase of the tube; the'grid is connected through one of the posts 29,.one of thejsupport wires 45, and the wire 62 to the grid terminal 13 at the base of the tube; and the filament is connected through one of the lilas i j ment terminals 12, through the wire 60the support 46, the supporting post 32, both filaments in series through thepost 34, the wire 61, and the other filament `terminal thereof. i

The insulating plates16 or 17 may be made f' of mica, quartz, or any` other desirable'materal suitable to use in vacuum tubes.

With the construction shown, it will 'be evident that the anode, grid, andthe filamentary cathode are positioned in such a manner that. there can be no movement with respect to each other. This makes it possible to design a tube with the grid very much closer to the cathode, and the anode very much` closer toI has been shown the invention is not neces-V i sarily limited to sucha construction, as one' with `a separately heated cathode might also be constructed-in the sameway as well as other types of tubes such as shield rid tubes or tubes having a smaller number o' elements v 4 such as rectifier tubes. While heavy supporting wires have been shown sealed in the press of the tube it is also evident that itis only necessary to use enough heavy supporting wires to mount the structure rigidly upon the press and the remaining wires maybe at' Y tached to the otheryelements by flexible connections if desired. f Y

Other modificationsV may be made in the unit as shown without departing from the spirit of the invention, and I do not desire @1F25 therefore to llimitthe invention to' what has been shown and described except as such limitations occur in the appended claims. What I claim is:

i1. In a vacuumtubehaving a stem, apfair @1230 of. spaced apartinsulat-ors, a plurality of sup- 'of spaced supports,=a plurality-of support :posts:extending'between said supports and terminating above saidI stem thereby combining with the-supports to provide a unitary 'I' structure, a ilamentary cathode positioned between'two of said support posts andfhaving ving one 'end attached toons, and the other endatta'ched .to the other, argrid mounted ruponanotherspair of saidsupport posts, and

S10 -anA anode mounteduponanother pair of said ysupportposts, thereby including the filament, grid, and anode-as part of theunitary :structure independent of any support from the stem.

2. Ina vacuum't-ube having a stem, apair Aport posts extending between said insulators 'and terminating above said stemthereby com- -blningwlth the insulators to provldeiauniv T-tary structure, -a JV-shaped filament positioned betweentwo of saidsupport posts, one

end .of said filament being welded to one of said suppOrt'pOstS, and the other end of'said Y a unitaryassembly'of elements including "a grid, cathode and anode, wherein there is aY postto which each ofsaid elements is secured, and means for holdingv all of said posts in wifixed relative positions independent of said stem, said Yunitary structure being supported entirely by -saidflead-'in wires from the stem.

4. .Inuan electron discharge device having lead-in wires .inthe stem, the combination of .a Iunitaryzassembly of elements including a grid, cathode-and anode, wherein there is a post to which 'each otsaid elements is secured, the length of each of said posts differing from theflength of the vpost next adjacent thereto, and means for holdingY allot said posts in fixed relative positions independent otsaid stem, said unitary structure being Vsupported entirely by said lead-in vwires from'the stem.

5..In an electron discharge device'havin'g Ylead-in wirescin the stem, the combination ot' a unitary assembly of elements including a grid, cathodeand anode, ywherein there is a` `postto which each of'said elements is secured,

and means for holding all of said posts in fixed relative positions independent of said stem, theseveral posts projecting through one of said holding `means 'distances differing each from the distance of projection of an ad- 306 ij-acentpost, said unitarys'tructure being supported yentirely by=said 4lea'din* wires from the stem. i A

-6. In an electron discharge deviceA having WALTER LOUIS AIIR-AHL.

lead-inv wiresin the stem, the/combination of i lead-in wiresin the stem, thecombination of :a unitary assembly of elementsY including a Vgrid,vcathode and Vgrid, -wherein there isa .post to which each of said elements is secured, vand means for holding all ofvsaid .posts rin 

